/*
 * Copyright (c) 2014, 2015, Oracle and/or its affiliates. All rights reserved.
 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
 *
 * This code is free software; you can redistribute it and/or modify it
 * under the terms of the GNU General Public License version 2 only, as
 * published by the Free Software Foundation.
 *
 * This code is distributed in the hope that it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
 *
 * You should have received a copy of the GNU General Public License version
 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
 * or visit www.oracle.com if you need additional information or have any
 * questions.
 *
 */

#include "precompiled.hpp"
#include "gc/g1/g1Allocator.hpp"
#include "gc/g1/g1CollectedHeap.inline.hpp"
#include "gc/g1/g1CollectorPolicy.hpp"
#include "gc/g1/g1MarkSweep.hpp"
#include "gc/g1/heapRegion.inline.hpp"
#include "gc/g1/heapRegionSet.inline.hpp"

void G1DefaultAllocator::init_mutator_alloc_region() {
  assert(_mutator_alloc_region.get() == NULL, "pre-condition");
  _mutator_alloc_region.init();
}

void G1DefaultAllocator::release_mutator_alloc_region() {
  _mutator_alloc_region.release();
  assert(_mutator_alloc_region.get() == NULL, "post-condition");
}

void G1Allocator::reuse_retained_old_region(EvacuationInfo& evacuation_info,
                                            OldGCAllocRegion* old,
                                            HeapRegion** retained_old) {
  HeapRegion* retained_region = *retained_old;
  *retained_old = NULL;
  assert(retained_region == NULL || !retained_region->is_archive(),
         err_msg("Archive region should not be alloc region (index %u)", retained_region->hrm_index()));

  // We will discard the current GC alloc region if:
  // a) it's in the collection set (it can happen!),
  // b) it's already full (no point in using it),
  // c) it's empty (this means that it was emptied during
  // a cleanup and it should be on the free list now), or
  // d) it's humongous (this means that it was emptied
  // during a cleanup and was added to the free list, but
  // has been subsequently used to allocate a humongous
  // object that may be less than the region size).
  if (retained_region != NULL &&
      !retained_region->in_collection_set() &&
      !(retained_region->top() == retained_region->end()) &&
      !retained_region->is_empty() &&
      !retained_region->is_humongous()) {
    retained_region->record_timestamp();
    // The retained region was added to the old region set when it was
    // retired. We have to remove it now, since we don't allow regions
    // we allocate to in the region sets. We'll re-add it later, when
    // it's retired again.
    _g1h->_old_set.remove(retained_region);
    bool during_im = _g1h->collector_state()->during_initial_mark_pause();
    retained_region->note_start_of_copying(during_im);
    old->set(retained_region);
    _g1h->_hr_printer.reuse(retained_region);
    evacuation_info.set_alloc_regions_used_before(retained_region->used());
  }
}

void G1DefaultAllocator::init_gc_alloc_regions(EvacuationInfo& evacuation_info) {
  assert_at_safepoint(true /* should_be_vm_thread */);

  _survivor_gc_alloc_region.init();
  _old_gc_alloc_region.init();
  reuse_retained_old_region(evacuation_info,
                            &_old_gc_alloc_region,
                            &_retained_old_gc_alloc_region);
}

void G1DefaultAllocator::release_gc_alloc_regions(uint no_of_gc_workers, EvacuationInfo& evacuation_info) {
  AllocationContext_t context = AllocationContext::current();
  evacuation_info.set_allocation_regions(survivor_gc_alloc_region(context)->count() +
                                         old_gc_alloc_region(context)->count());
  survivor_gc_alloc_region(context)->release();
  // If we have an old GC alloc region to release, we'll save it in
  // _retained_old_gc_alloc_region. If we don't
  // _retained_old_gc_alloc_region will become NULL. This is what we
  // want either way so no reason to check explicitly for either
  // condition.
  _retained_old_gc_alloc_region = old_gc_alloc_region(context)->release();
  if (_retained_old_gc_alloc_region != NULL) {
    _retained_old_gc_alloc_region->record_retained_region();
  }

  if (ResizePLAB) {
    _g1h->alloc_buffer_stats(InCSetState::Young)->adjust_desired_plab_sz(no_of_gc_workers);
    _g1h->alloc_buffer_stats(InCSetState::Old)->adjust_desired_plab_sz(no_of_gc_workers);
  }
}

void G1DefaultAllocator::abandon_gc_alloc_regions() {
  assert(survivor_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");
  assert(old_gc_alloc_region(AllocationContext::current())->get() == NULL, "pre-condition");
  _retained_old_gc_alloc_region = NULL;
}

G1PLAB::G1PLAB(size_t gclab_word_size) :
  PLAB(gclab_word_size), _retired(true) { }

HeapWord* G1ParGCAllocator::allocate_direct_or_new_plab(InCSetState dest,
                                                        size_t word_sz,
                                                        AllocationContext_t context) {
  size_t gclab_word_size = _g1h->desired_plab_sz(dest);
  if (word_sz * 100 < gclab_word_size * ParallelGCBufferWastePct) {
    G1PLAB* alloc_buf = alloc_buffer(dest, context);
    alloc_buf->retire();

    HeapWord* buf = _g1h->par_allocate_during_gc(dest, gclab_word_size, context);
    if (buf == NULL) {
      return NULL; // Let caller handle allocation failure.
    }
    // Otherwise.
    alloc_buf->set_word_size(gclab_word_size);
    alloc_buf->set_buf(buf);

    HeapWord* const obj = alloc_buf->allocate(word_sz);
    assert(obj != NULL, "buffer was definitely big enough...");
    return obj;
  } else {
    return _g1h->par_allocate_during_gc(dest, word_sz, context);
  }
}

G1DefaultParGCAllocator::G1DefaultParGCAllocator(G1CollectedHeap* g1h) :
  G1ParGCAllocator(g1h),
  _surviving_alloc_buffer(g1h->desired_plab_sz(InCSetState::Young)),
  _tenured_alloc_buffer(g1h->desired_plab_sz(InCSetState::Old)) {
  for (uint state = 0; state < InCSetState::Num; state++) {
    _alloc_buffers[state] = NULL;
  }
  _alloc_buffers[InCSetState::Young] = &_surviving_alloc_buffer;
  _alloc_buffers[InCSetState::Old]  = &_tenured_alloc_buffer;
}

void G1DefaultParGCAllocator::retire_alloc_buffers() {
  for (uint state = 0; state < InCSetState::Num; state++) {
    G1PLAB* const buf = _alloc_buffers[state];
    if (buf != NULL) {
      buf->flush_and_retire_stats(_g1h->alloc_buffer_stats(state));
    }
  }
}

void G1DefaultParGCAllocator::waste(size_t& wasted, size_t& undo_wasted) {
  wasted = 0;
  undo_wasted = 0;
  for (uint state = 0; state < InCSetState::Num; state++) {
    G1PLAB * const buf = _alloc_buffers[state];
    if (buf != NULL) {
      wasted += buf->waste();
      undo_wasted += buf->undo_waste();
    }
  }
}

G1ArchiveAllocator* G1ArchiveAllocator::create_allocator(G1CollectedHeap* g1h) {
  // Create the archive allocator, and also enable archive object checking
  // in mark-sweep, since we will be creating archive regions.
  G1ArchiveAllocator* result =  new G1ArchiveAllocator(g1h);
  G1MarkSweep::enable_archive_object_check();
  return result;
}

bool G1ArchiveAllocator::alloc_new_region() {
  // Allocate the highest free region in the reserved heap,
  // and add it to our list of allocated regions. It is marked
  // archive and added to the old set.
  HeapRegion* hr = _g1h->alloc_highest_free_region();
  if (hr == NULL) {
    return false;
  }
  assert(hr->is_empty(), err_msg("expected empty region (index %u)", hr->hrm_index()));
  hr->set_archive();
  _g1h->_old_set.add(hr);
  _g1h->_hr_printer.alloc(hr, G1HRPrinter::Archive);
  _allocated_regions.append(hr);
  _allocation_region = hr;

  // Set up _bottom and _max to begin allocating in the lowest
  // min_region_size'd chunk of the allocated G1 region.
  _bottom = hr->bottom();
  _max = _bottom + HeapRegion::min_region_size_in_words();

  // Tell mark-sweep that objects in this region are not to be marked.
  G1MarkSweep::mark_range_archive(MemRegion(_bottom, HeapRegion::GrainWords));

  // Since we've modified the old set, call update_sizes.
  _g1h->g1mm()->update_sizes();
  return true;
}

HeapWord* G1ArchiveAllocator::archive_mem_allocate(size_t word_size) {
  assert(word_size != 0, "size must not be zero");
  if (_allocation_region == NULL) {
    if (!alloc_new_region()) {
      return NULL;
    }
  }
  HeapWord* old_top = _allocation_region->top();
  assert(_bottom >= _allocation_region->bottom(),
         err_msg("inconsistent allocation state: " PTR_FORMAT " < " PTR_FORMAT,
                 p2i(_bottom), p2i(_allocation_region->bottom())));
  assert(_max <= _allocation_region->end(),
         err_msg("inconsistent allocation state: " PTR_FORMAT " > " PTR_FORMAT,
                 p2i(_max), p2i(_allocation_region->end())));
  assert(_bottom <= old_top && old_top <= _max,
         err_msg("inconsistent allocation state: expected "
                 PTR_FORMAT " <= " PTR_FORMAT " <= " PTR_FORMAT,
                 p2i(_bottom), p2i(old_top), p2i(_max)));

  // Allocate the next word_size words in the current allocation chunk.
  // If allocation would cross the _max boundary, insert a filler and begin
  // at the base of the next min_region_size'd chunk. Also advance to the next
  // chunk if we don't yet cross the boundary, but the remainder would be too
  // small to fill.
  HeapWord* new_top = old_top + word_size;
  size_t remainder = pointer_delta(_max, new_top);
  if ((new_top > _max) ||
      ((new_top < _max) && (remainder < CollectedHeap::min_fill_size()))) {
    if (old_top != _max) {
      size_t fill_size = pointer_delta(_max, old_top);
      CollectedHeap::fill_with_object(old_top, fill_size);
      _summary_bytes_used += fill_size * HeapWordSize;
    }
    _allocation_region->set_top(_max);
    old_top = _bottom = _max;

    // Check if we've just used up the last min_region_size'd chunk
    // in the current region, and if so, allocate a new one.
    if (_bottom != _allocation_region->end()) {
      _max = _bottom + HeapRegion::min_region_size_in_words();
    } else {
      if (!alloc_new_region()) {
        return NULL;
      }
      old_top = _allocation_region->bottom();
    }
  }
  _allocation_region->set_top(old_top + word_size);
  _summary_bytes_used += word_size * HeapWordSize;

  return old_top;
}

void G1ArchiveAllocator::complete_archive(GrowableArray<MemRegion>* ranges,
                                          size_t end_alignment_in_bytes) {
  assert((end_alignment_in_bytes >> LogHeapWordSize) < HeapRegion::min_region_size_in_words(),
          err_msg("alignment " SIZE_FORMAT " too large", end_alignment_in_bytes));
  assert(is_size_aligned(end_alignment_in_bytes, HeapWordSize),
         err_msg("alignment " SIZE_FORMAT " is not HeapWord (%u) aligned", end_alignment_in_bytes, HeapWordSize));

  // If we've allocated nothing, simply return.
  if (_allocation_region == NULL) {
    return;
  }

  // If an end alignment was requested, insert filler objects.
  if (end_alignment_in_bytes != 0) {
    HeapWord* currtop = _allocation_region->top();
    HeapWord* newtop = (HeapWord*)align_pointer_up(currtop, end_alignment_in_bytes);
    size_t fill_size = pointer_delta(newtop, currtop);
    if (fill_size != 0) {
      if (fill_size < CollectedHeap::min_fill_size()) {
        // If the required fill is smaller than we can represent,
        // bump up to the next aligned address. We know we won't exceed the current
        // region boundary because the max supported alignment is smaller than the min
        // region size, and because the allocation code never leaves space smaller than
        // the min_fill_size at the top of the current allocation region.
        newtop = (HeapWord*)align_pointer_up(currtop + CollectedHeap::min_fill_size(),
                                             end_alignment_in_bytes);
        fill_size = pointer_delta(newtop, currtop);
      }
      HeapWord* fill = archive_mem_allocate(fill_size);
      CollectedHeap::fill_with_objects(fill, fill_size);
    }
  }

  // Loop through the allocated regions, and create MemRegions summarizing
  // the allocated address range, combining contiguous ranges. Add the
  // MemRegions to the GrowableArray provided by the caller.
  int index = _allocated_regions.length() - 1;
  assert(_allocated_regions.at(index) == _allocation_region,
         err_msg("expected region %u at end of array, found %u",
                 _allocation_region->hrm_index(), _allocated_regions.at(index)->hrm_index()));
  HeapWord* base_address = _allocation_region->bottom();
  HeapWord* top = base_address;

  while (index >= 0) {
    HeapRegion* next = _allocated_regions.at(index);
    HeapWord* new_base = next->bottom();
    HeapWord* new_top = next->top();
    if (new_base != top) {
      ranges->append(MemRegion(base_address, pointer_delta(top, base_address)));
      base_address = new_base;
    }
    top = new_top;
    index = index - 1;
  }

  assert(top != base_address, err_msg("zero-sized range, address " PTR_FORMAT, p2i(base_address)));
  ranges->append(MemRegion(base_address, pointer_delta(top, base_address)));
  _allocated_regions.clear();
  _allocation_region = NULL;
};